This proposal seeks support to acquire a state-of-the-art Hitachi Medical Systems ETG-4000 functional near infrared spectroscopy (fNIRS) multi-channel optical topography system for the study of the brain systems underpinning various aspects of human cognitive and social functioning, as well as their typical and atypical development across the lifespan, from early infancy to late adulthood. Clinical and basic scientists from multiple disciplines and departments at Yale University stand poised to use the proposed brain imaging system to make field-leading contributions in the context of furthering their National Institutes of Health-funded, translational research programs. These research programs address critical questions in a number of important areas including the cognitive neuroscience of autism, developmental cognitive neuroscience, developmental psychopathology, aspects of high-level cognition including memory and executive control, visual cognition, neuroimaging methods development, and social neuroscience. Scientists at Yale University have been at the forefront of advances in neuroimaging techniques, particularly as they are applied to understanding the human mind and its development. While much progress has been made, fundamental questions about typical and atypical brain function remain to be addressed with the help of the requested instrument.